Leaning vehicle

ABSTRACT

A leaning vehicle has a frame pivotally connected to a shock tower, at least one biasing member connected to the frame, front left and right suspension assemblies each having a shock absorber connected to the shock tower, two front ground engaging members, a rear suspension assembly, and a rear ground engaging member. The at least one biasing member applies a first force to the shock tower when the frame has pivoted relative to the shock tower. When the frame pivots left, a force is transferred to the front left ground engaging member by the left shock absorber to apply a force having a downward component to the front left ground engaging member. When the frame pivots right, a force is transferred to the front right ground engaging member by the right shock absorber to apply a force having a downward component to the front right ground engaging member.

CROSS-REFERENCE

The present application claims priority to U.S. Provisional PatentApplication No. 61/860,587, filed Jul. 31, 2013, is aContinuation-In-Part of U.S. patent application Ser. No. 13/955,830,filed Jul. 31, 2013, and through U.S. patent application Ser. No.13/955,830, claims priority to U.S. Provisional Patent Application No.61/677,621, filed Jul. 31, 2012, the entirety of all three of which isincorporated herein by reference.

TECHNICAL FIELD

The present application relates to leaning vehicles.

BACKGROUND

Typically, snowmobiles have two front skis connected to a handlebar anda rear endless track connected to an engine to propel the snowmobile. Insuch typical snowmobiles, the snowmobile is steered by turning thehandlebar in the direction in which the driver wants to turn. This isknown as steer-in-direction. During a turn, the suspension assemblyconnected to the ski on the outside of the turn is compressed, causingthe snowmobile to roll slightly toward the outside of the turn, whichthe driver can compensate by leaning toward the inside of the turn.

In other vehicles, such as motorcycles, the vehicle is steered by whatis known as countersteering. In a motorcycle for example, the motorcycleturns by leaning in the direction of the turn. To achieve this leaning,the driver momentarily turns the handlebar in the direction opposite tothe direction of the turn (i.e. the driver countersteers).

Driving a vehicle that can lean into a turn offers a much differentdriving experience than driving a vehicle that is steer-in-direction. Itwould be desirable to at least some drivers to have the drivingexperience of a leaning vehicle on a vehicle having three groundengaging members such as a snowmobile.

U.S. Pat. No. 7,648,148 B1, issued Jan. 19, 2010, and U.S. Pat. No.7,530,419 B2, issued May 12, 2009, describe three-wheel vehicles thatcan lean in a turn. In vehicles of this type, the frame of the vehicleis pivotally connected to a shock tower (also known as a transfer frame)and the front shock absorbers associated with the two front wheels areconnected at their upper end to the shock tower. During a turn, theframe pivots into the turn like on a motorcycle, but the shock towerremains essentially vertical. As a result, the front shock absorbers donot get compressed due to the leaning of the frame.

Although leaning the frame of a vehicle having three ground engagingmembers during a turn compensates for the tendency of the vehicle rollslightly toward the outside of the turn, it may not completelycompensate for this tendency. As such, even with the leaning of theframe, during a turn the weight on the front ground engaging memberdisposed on the inside of the turn is reduced.

As such, there is a need for a system for compensating the weightreduction on the front ground engaging member disposed on an inside of aturn during the turn for a leaning vehicle having at least three groundengaging members with the frame of the vehicle being pivotable relativeto a shock tower of such a vehicle.

SUMMARY

One object of the present invention is to ameliorate at least some ofthe inconveniences of the prior art.

In one aspect, a leaning vehicle has a frame having a front portion anda rear portion, a straddle seat mounted on the frame, a motor supportedby the frame, a shock tower pivotally connected to the front portion ofthe frame, the frame being pivotable relative to the shock tower about apivot axis between an upright position and a plurality of leaningpositions, at least one biasing member connected to the frame, the atleast one biasing member being adapted to apply a first force to theshock tower when the frame pivots relative to the shock tower, a frontleft suspension assembly and a front right suspension assemblyoperatively connected to the front portion of the frame, a front leftground engaging member operatively connected to the front leftsuspension assembly, a front right ground engaging member operativelyconnected to the front right suspension assembly, a steering assemblyoperatively connected to the front left ground engaging member and tothe front right ground engaging member to steer the vehicle, thesteering assembly having a steering column supported by the frame and ahandlebar connected to the steering column, a rear suspension assemblyoperatively connected to the rear portion of the frame and a rear groundengaging member operatively connected to the rear suspension assembly.Each of the front left suspension assembly and the front rightsuspension assembly has a leg operatively connected to a correspondingone of the front left ground engaging member and the front right groundengaging member, the leg being rotatable about a steering axis, an uppersuspension arm having a first end pivotally connected to the frame and asecond end pivotally connected to the leg, a lower suspension arm havinga first end pivotally connected to the frame and a second end pivotallyconnected to the leg, the lower suspension arm being lower than theupper suspension arm, and a shock absorber having an upper end connectedto the shock tower and a lower end connected to the lower suspensionarm. The at least one biasing member is adapted to apply the first forceto the shock tower when the frame has pivoted left relative to the shocktower. The first force is transferred to the front left ground engagingmember by the shock absorber of the front left suspension assembly toapply a second force having a downward component to the front leftground engaging member. The at least one biasing member being adapted toapply the first force to the shock tower when the frame has pivotedright relative to the shock tower. The first force being transferred tothe front right ground engaging member by the shock absorber of thefront right suspension assembly to apply a third force having a downwardcomponent to the front right ground engaging member.

In a further aspect, the at least one biasing member is a first biasingmember and a second biasing member. The first biasing member is adaptedto apply the first force to the shock tower when the frame has pivotedleft relative to the shock tower. The second biasing member is adaptedto apply the first force to the shock tower when the frame has pivotedright relative to the shock tower.

In an additional aspect, the at least one biasing member is at least onespring.

In a further aspect, at least one bumper is connected to the shocktower. The at least one spring is adapted to abut the at least onebumper when the frame pivots relative to the shock tower.

In an additional aspect, the at least one spring is spaced from the atleast one bumper when the frame is in the upright position.

In a further aspect, the at least one bumper includes a left bumperconnected to a left side of the shock tower and a right bumper connectedto a right side of the shock tower. The at least one spring includes aleft spring and a right spring. The right spring is adapted to apply thefirst force to the right bumper when the frame has pivoted left relativeto the shock tower. The left spring being adapted to apply the firstforce to the left bumper when the frame has pivoted right relative tothe shock tower.

In an additional aspect, the left and right springs are spaced from theleft and right bumpers when the frame is in the upright position.

In a further aspect, a left post is connected to the frame. The leftpost is disposed to a left of the pivot axis and below the pivot axiswhen the frame is in the upright position. A right post is connected tothe frame. The right post is disposed to a right of the pivot axis andbelow the pivot axis when the frame is in the upright position. The leftand right springs are torsion springs. The left spring is disposedaround the left post and the right spring is disposed around the rightpost.

In an additional aspect, a rack is connected to the shock tower. Therack is movable with the shock tower relative to the frame. The leftbumper is connected to a left side of the rack and the right bumper isconnected to a right side of the rack.

In a further aspect, a left stopper is connected to one of the frame andthe shock tower. The left stopper is adapted to abut another one of theframe and the shock tower when the frame pivots left relative to theshock tower by a first angle thereby limiting pivoting of the framerelative to the shock tower toward the left. A right stopper isconnected to one of the frame and the shock tower. The right stopper isadapted to abut another one of the frame and the shock tower when theframe pivots right relative to the shock tower by a second angle therebylimiting pivoting of the frame relative to the shock tower toward theright.

In an additional aspect, the left stopper is a first left stopper andthe right stopper is a first right stopper. A second left stopper isconnected to one of the frame and the lower suspension arm of the frontleft suspension assembly. The second left stopper is adapted to abutanother one of the frame and the lower suspension arm of the front leftsuspension assembly when the frame has pivoted left relative to theshock tower by the first angle and the shock absorber of the leftsuspension assembly is compressed by a first amount thereby limitingleaning of the vehicle relative to vertical toward the left. A secondright stopper is connected to one of the frame and the lower suspensionarm of the front right suspension assembly. The second right stopper isadapted to abut another one of the frame and the lower suspension arm ofthe front right suspension assembly when the frame has pivoted rightrelative to the shock tower by the second angle and the shock absorberof the right suspension assembly is compressed by a second amountthereby limiting leaning of the vehicle relative to vertical toward theright.

In a further aspect, when one of the left stopper and the right stopperabuts the other one of the frame and the shock tower, the steeringcolumn is disposed laterally outward of a triangle formed by connectionpoints of the shock absorbers with the shock tower and the pivot axis.

In an additional aspect, a rack is connected to the shock tower. Therack defines a central aperture. A pin is operatively connected to theframe and is selectively movable inside the central aperture. The pinlocks the frame in the upright position when the pin is received insidethe central aperture.

In a further aspect, the rack has a left ratchet surface and a rightratchet surface. The pin is further selectively movable to abut the leftand right ratchet surfaces when the frame is pivoted left and rightrespectively relative to the shock tower. When the pin abuts the leftratchet surface, the left ratchet surface prevents the frame frompivoting further toward the left and permits the frame from pivotingtoward the right up to the upright position where the pin is received inthe central aperture. When the pin abuts the right ratchet surface, theright ratchet surface prevents the frame from pivoting further towardthe right and permits the frame from pivoting toward the left up to theupright position where the pin is received in the central aperture.

In an additional aspect, a section of a brake disc is connected to oneof the frame and the shock tower. A caliper and brake pad assembly isconnected to another one of the frame and the shock tower. The caliperand brake bad assembly is adapted to apply a braking force to thesection of the brake disc.

In a further aspect, the vehicle is a snowmobile. The rear portion ofthe frame includes a tunnel. The front left ground engaging member is aleft ski. The front right ground engaging member is a right ski. Therear ground engaging member is an endless track disposed at least inpart under the tunnel. The leg of the front left suspension assembly isa left ski leg. The leg of the front right suspension assembly is aright ski leg.

In an additional aspect, the endless drive track has a generally arcuatelateral profile.

In a further aspect, when the frame is in a maximum leaning positiontoward a left and the handlebar is turned to steer the skis toward theleft, a rear end of the left ski is received in a left recess defined ina left side of the snowmobile. When the frame is in a maximum leaningposition toward a right and the handlebar is turned to steer the skistoward the right, a rear end of the right ski is received in a rightrecess defined in a right side of the snowmobile.

In an additional aspect, a left side panel is connected to the framerearward of the shock absorber of the front left suspension assembly. Aright side panel is connected to the frame rearward of the shockabsorber of the front right suspension assembly. The left recess isdisposed rearward of the shock absorber of the front left suspensionassembly and forward of the left side panel. The right recess isdisposed rearward of the shock absorber of the front right suspensionassembly and forward of the right side panel.

In a further aspect, at least one blade is connected to at least oneside of each of the left and right skis. The blades extend below thefloatation surfaces of the left and right skis.

In an additional aspect, when the frame is in the upright position andthe skis are steered in a straight ahead direction, the blades areparallel to a pivot axis of the steering column.

In a further aspect, when the frame is in a maximum leaning positiontoward a left, a center of gravity of the snowmobile is disposed to aleft of a contact point between the left ski and a ground. When theframe is in a maximum leaning position toward a right, the center ofgravity of the snowmobile is disposed to a right of a contact pointbetween the right ski and the ground.

In an additional aspect, fairings are connected to the frame. When theframe is in a maximum leaning position toward a left, a lowest part ofthe fairings when the frame is in the maximum leaning position towardthe left is disposed vertically higher than a line passing through alowest point of the front left ground engaging member and a lowest pointof the front right ground engaging member when the frame is in themaximum leaning position toward the left. When the frame is in a maximumleaning position toward a right, a lowest part of the fairings when theframe is in the maximum leaning position toward the right is disposedvertically higher than a line passing through a lowest point of thefront left ground engaging member and a lowest point of the front rightground engaging member when the frame is in the maximum leaning positiontoward the right.

In a further aspect, a pitman arm is connected to the steering column.The pitman arm is pivotable with the steering column about a pivot axisof the steering column. Steering rods connect the pitman arm to thelegs. The steering axes of the legs are parallel to the pivot axis ofthe steering column when the frame is in the upright position.

In an additional aspect, for each of the front left suspension assemblyand the front right suspension assembly the first end of the uppersuspension arm is pivotally connected to the frame about an uppersuspension arm pivot axis and the first end of the lower suspension armis pivotally connected to the frame about a lower suspension arm pivotaxis. The upper suspension arm pivot axes and the lower suspension armpivot axes are perpendicular to the pivot axis of the steering column.

For purposes of this application, terms related to spatial orientationsuch as forwardly, rearwardly, upwardly, downwardly, left, and right,are as they would normally be understood by a driver of the vehiclesitting thereon in a normal riding position. Also, the term “groundengaging member” refers to a component of a vehicle making contact withthe ground and on which the vehicle is displaced. Examples of groundengaging members include, but are not limited to, skis, wheels andendless tracks.

Embodiments of the present invention each have at least one of theabove-mentioned object and/or aspects, but do not necessarily have allof them. It should be understood that some aspects of the presentinvention that have resulted from attempting to attain theabove-mentioned object may not satisfy this object and/or may satisfyother objects not specifically recited herein.

Additional and/or alternative features, aspects, and advantages ofembodiments of the present invention will become apparent from thefollowing description, the accompanying drawings, and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, as well as otheraspects and further features thereof, reference is made to the followingdescription which is to be used in conjunction with the accompanyingdrawings, where:

FIG. 1 is a left side elevation view of a leaning snowmobile;

FIG. 2 is a left side elevation view of a frame, front suspensionassemblies, skis and exhaust system of the snowmobile of FIG. 1;

FIG. 3 is a perspective view taken from a front left side of a frontportion of the snowmobile components of FIG. 2;

FIG. 4 is a front elevation view of the snowmobile components of FIG. 2;

FIG. 5 is a left side elevation view of a front portion of thesnowmobile components of FIG. 2;

FIG. 6 is a right side elevation view of a front portion of thesnowmobile components of FIG. 2;

FIG. 7 is a perspective view taken from a front left side of a frontportion of the snowmobile components of FIG. 2, with a portion of theframe and of the left suspension assembly removed;

FIG. 8 is a cross-sectional view of the snowmobile components of FIG. 2taken through line 8-8 of FIG. 2;

FIG. 9 is a perspective view taken from a front left side of a frontportion of the snowmobile components of FIG. 2 shown leaning toward aleft side;

FIG. 10 is a front elevation view of the snowmobile components of FIG. 2shown leaning toward a left side;

FIG. 11 is a schematic plan view of an outer portion of a track for thesnowmobile of FIG. 1; and

FIG. 12 is a cross-sectional view of the track of FIG. 11 taken throughline 12-12 of FIG. 11.

FIG. 13 is a perspective view, taken from a front, left side, of analternative embodiment of a leaning snowmobile;

FIG. 14 is a front a front elevation view of the snowmobile of FIG. 13;

FIG. 15 is a top plan view of the snowmobile of FIG. 13;

FIG. 16 is a left side elevation view of the front portion of thesnowmobile of FIG. 13;

FIG. 17 is a left side elevation view of a left ski, a front leftsuspension assembly and elements of a steering assembly of thesnowmobile of FIG. 13;

FIG. 18 is a perspective view taken from a rear, left side of frontportion of the frame, the front suspension assemblies and the skis ofthe snowmobile of FIG. 13;

FIG. 19 is a front elevation view of the snowmobile components of FIG.18 shown in an upright position;

FIG. 20 is a front elevation view of the snowmobile components of FIG.18 shown leaning toward a left side;

FIG. 21 is a front elevation view of the snowmobile components of FIG.18 shown leaning further toward the left side, with the frame removedfor clarity;

FIG. 22 is a front elevation view of the snowmobile of FIG. 13 shownleaning toward the left side, with some fairings removed;

FIG. 23 is a left side elevation view of a front portion of the frame,the steering assembly, a left side fairing, the front suspensionassemblies and the left ski of the snowmobile of FIG. 13 shown leaningtoward the left side, with the left ski being countersteered toward theleft and a front part of the left ski being pivoted downward; and

FIG. 24 is a close-up perspective view taken from a front, left side ofan alternative embodiment of a shock tower being provided with a brake.

DETAILED DESCRIPTION

A leaning snowmobile 10 will be described below. It should be understoodthat aspects of the leaning snowmobile 10 could be applied to othertypes of leaning vehicles having three or more ground engaging memberssuch as, but not limited to, a three-wheeled vehicle having left andright front wheels and one laterally centered rear wheel.

Referring to FIG. 1, the snowmobile 10 will be described. The snowmobile10 has a front end 12 and a rear end 14, which are defined consistentlywith the forward travel direction of the snowmobile. The snowmobile 10has a frame 16 that includes a tunnel 18, an engine cradle portion 20(FIG. 2) and a front suspension assembly portion 22. A motor, which inthe present embodiment is an engine 24 that is schematically illustratedin FIG. 1, is carried by the engine cradle portion 20 of the frame 16.The engine 24 is a two-stroke, two-cylinder internal combustion enginehaving two-cylinders, but it is contemplated that the engine 24 could beany type of motor, such as, for example, a four-stroke internalcombustion engine or an electric motor. A ski and steering assembly isprovided, in which two skis 26 are positioned at the front end 12 of thesnowmobile 10, and are attached to the front suspension assembly portion22 of the frame 16 through front suspension assemblies 28 that will bedescribed in greater detail below. The skis 26 are operatively connectedto a steering assembly including a steering column 30 and a handlebar 32as will be described in greater detail below.

An endless drive track 34 is positioned at the rear end 14 of thesnowmobile 10 and is disposed under the tunnel 18. The endless drivetrack 34 is operatively connected to the engine 24 through a reductiondrive (not shown) and a belt transmission system 36 which isschematically illustrated by broken lines. In one example, the belttransmission system 36 is a continuously variable transmission (CVT).Drive sprockets (not shown) disposed at a front of the tunnel 18 insidethe drive track 34 are driven by the reduction drive and engage drivelugs 37 (FIG. 12) extending from an inner surface of the drive track 34and/or apertures (not shown) formed along the length of the drive track34. Thus, the endless drive track 34 is driven to run about a rearsuspension assembly 38 for propulsion of the snowmobile 10. Terrain lugs40A, B (only some of which have been labeled for clarity) are disposedcircumferentially about the outer side of the drive track 34 to providetraction to the drive track 34. Although one embodiment is provided, thespecific distribution pattern and dimensions of the terrain lugs willvary depending on the application and desired characteristics of thedrive track 34. The drive track 34 will be described in greater detailbelow. The rear suspension assembly 38 is connected to the tunnel 18.The rear suspension assembly 38 includes a pair of slide rails 42, afront transverse shaft (not shown) connected to the tunnel 18, a shockabsorber 44 connected between the front transverse shaft and the sliderails 42, and front suspension arms 46 connected between the fronttransverse shaft and the slide rails 42. The rear suspension assembly 38also includes a rear transverse shaft (not shown) connected to thetunnel 18, a shock absorber 48 connected between the rear transverseshaft and the slide rails 42, rear suspension arms 50 connected betweenthe rear transverse shaft and the slide rails 42, and torsion springs 52(only partially shown) disposed around the rear transverse shaft andhaving an end supported by the slide rails 42. A number of wheels 54 areconnected to the slide rails 42 and the front and rear transverse shaftand roll along the inner surface of the endless drive track 34 when thesnowmobile 10 is in movement. The above-described rear suspensionassembly 38 is one possible embodiment of a rear suspension assemblythat can be used with the snowmobile 10. It is contemplated that otherembodiments of rear suspension assemblies can be used with thesnowmobile 10.

At the front end 12 of the snowmobile 10, there are provided fairings 56that enclose the engine 24, the reduction drive and the belttransmission system 36, thereby providing an external shell that notonly protects these components, but also make the snowmobile 10 moreaesthetically pleasing. The fairings 56 include one or more panels thatcan be opened to allow access to the engine 24, the reduction drive, thebelt transmission system 36 and other components of the snowmobile 10disposed inside the fairings 56. A windshield 58 is connected to thefairings 56 near the front end 12 of the snowmobile 10, or mayalternatively be attached directly to the handlebar 32. The windshield58 acts as a windscreen to lessen the force of the air on the riderwhile the snowmobile 10 is moving.

A seat 60 is connected to and disposed on the tunnel 18. Two footrests62 extend laterally from the tunnel 18 on opposite sides of thesnowmobile 10 below the seat 60 to accommodate the rider's feet.

The engine 24 receives fuel from a fuel supply system (not shown)including a fuel tank and fuel injectors. Air is supplied to the engine24 by an air intake system (not shown) including an airbox, a throttlebody disposed downstream of the air box, and an air intake manifoldfluidly communicating the throttle body with air intake ports (notshown) of the engine 24 disposed on a rear side thereof. Otherembodiments of air intake systems are contemplated. For example, onethrottle body could be provide per cylinder of the engine 24, and assuch the air intake manifold would be omitted and, if necessary,replaced by one air intake pipe per cylinder for fluidly communicatingeach throttle body to its corresponding air intake port. Exhaust gasesexit the engine 24 via the exhaust ports (not shown) of the engine 24disposed on a front side thereof. From the exhaust ports, the exhaustgases flow into an exhaust manifold (not shown), then into an exhaustpipe in the form of a tuned pipe 64 (FIG. 2), a muffler 66 (FIG. 2) andfinally out to the atmosphere. As can be seen in FIGS. 2 to 10, thetuned pipe 64 is generally U-shaped and extends in part over thesuspension assembly portion 22. The muffler 66 is disposed on a rightside of the engine cradle 20. Other embodiments of exhaust systems arecontemplated.

Turning now to FIGS. 2 to 10, the suspension assembly portion 22 will bedescribed in more detail. The suspension assembly portion 22 has ametallic extruded frame member 68 fastened to the front of the enginecradle 20. The extruded frame member 68 is laterally centered. It iscontemplated that the extruded frame member 68 could be replaced by aplurality of beams, tubes and/or brackets that are fastened, bonded orwelded together. A sheet metal plate 70 is disposed forward of theextruded frame member 68 and is fastened along its top to the extrudedframe member 68. Side plates 72 are fastened to the left and right sidesof the extruded frame member 68 and to the front of the engine cradle20. The plate 70 has side tabs disposed between the side plates 72 andthe extruded frame member 68 and as such the tabs are fastened to theextruded frame members 68 by the fasteners used to fasten the sideplates to the extruded frame member 68. The lower portion of the plate70 is disposed between a beam 74 and the extruded frame member 68. Thebeam 74 is fastened to the extruded frame member 68 by fasteners passingthough the lower portion of the plate 70. A triangular member 76 (FIG.7) is fastened to the front of the upper part of the plate 70 and islaterally centered. Left and right stopper holders 78 are fastened tothe side plates 72 and the side tabs of the plate 70 on either side ofthe suspension assembly portion 22. Left and right stoppers 80 arefastened to and extend downwardly from their respective stopper holders78. It is contemplated that the stoppers 80 could be integrally formedwith the stopper holders 78 or some other portion of the suspensionassembly portion 22. In the illustrated embodiment, the stoppers 80 havea cylindrical metal core with a rubberized outer shell, but other typesof stoppers are contemplated. A sheet metal top plate 82 is fastenedbetween the upper forward portions of the side plates 72. A sheet metalfront plate 84 is fastened along its upper edge to the front of the topplate 82 and along its lower edge to the front of the beam 74. As can beseen, the front plate 84 is spaced from the plate 70. The front plate84, the plate 70, the beam 74 and the top plate 82 define a cavitytherebetween. A bracket 86 is fastened to the lower portion of the frontplate 84 and has a tab that is longitudinally spaced from the frontplate 84. It is contemplated that the components of the suspensionassembly portion 22 could be made of materials other than metal. Forexample, it is contemplated that at least some the components of thesuspension assembly portion 22 could be made of plastic or compositematerial. It is also contemplated that at least some of the componentsof the suspension assembly portion 22 could be bonded, welded orintegrally formed with each other instead of being fastened. It is alsocontemplated that one or more of the plates 70, 82, 84 could be replacedby one or more beams, tubes and/or brackets that are fastened, bonded orwelded together.

A shock tower 88 is disposed between the plates 70 and 84. As can beseen in FIGS. 5 and 6, a portion of the tuned pipe 64 extends forwardlyof the shock tower 88. The shock tower 88 is fixedly mounted onto ashaft 90 (FIG. 7). The ends of the shaft 90 are disposed inside bearings(not shown). The front bearing is received in an aperture (not shown) inthe plate 84 and the rear bearing is received in an aperture (not shown)in the plate 70. As a result, and as will be described in greater detailbelow, the shaft 90 and the shock tower 88 can pivot about a pivot axis92 relative to the frame 16 of the snowmobile 10. The pivot axis 92 islaterally aligned with the longitudinal centerline of the snowmobile 10when the frame 16 is in an upright position (i.e. the position of theframe 16 shown in FIGS. 2 to 8). The shock tower 88 is generallytriangular in shape, but other shapes are contemplated. For example, theshock tower 88 could be generally T-shaped with a horizontal bar of theT being at a top of the shock tower 88. As best seen in FIG. 7, left andright stoppers 94 are fastened to the top of the shock tower 88. Thestoppers 94 are positioned along the top of the shock tower 88 such thatwhen the frame 16 leans by a predetermined angle relative to the shocktower 88, the corresponding stopper 94 (i.e. the left stopper 94 whenthe frame 16 leans left and the right stopper 94 when the frame 16 leansright) makes contact with a corresponding one of the contact surfaces 96(FIG. 7) defined by the triangular member 76, as will be described ingreater detail below. In the illustrated embodiment, the stoppers 94have a cylindrical metal core with a rubberized outer shell, but othertypes of stoppers are contemplated. It is contemplated that the stoppers94 could be integrally formed with the shock tower 88. It is alsocontemplated that the stoppers 94 could be connected to the triangularmember 76, or some other portion of the suspension assembly portion 22,and that the contact surfaces 96 could be defined on the shock tower 88.As can be seen in FIG. 7, when the frame 16 is in the upright positionas shown, the stoppers 94 are vertically higher than the stoppers 80.

A rack 98 is disposed between the plates 70 and 84 and is fastened tothe front of the shock tower 88 as shown in FIG. 8. As such, the rack 98is fixed relative to the shock tower 88. As can also be seen in FIG. 8,the rack 98 has a central aperture 100 located at a lateral center ofthe rack 98 at a top thereof. The rack 98 also has left and rightforwardly facing ratchet surfaces 102 on either sides of the centralaperture 100. The central aperture 100 and the ratchet surfaces 102generally define an arc having the pivot axis 92 as a center ofcurvature.

A locking mechanism 104 is mounted onto the front of the plate 84. Thelocking mechanism 104 includes an electric motor 106, a cylinder 108 anda pin 110 (FIG. 8). The pin 110 is slidably received in the cylinder 108and passes through an aperture (not shown) in the plate 84 in alignmentwith the central aperture 100 of the rack 98 when the frame 16 is in theupright position. The electric motor 106 selectively slides the pin 110rearward such that the pin 110 can be received in the central aperture100 of the rack 98 when the frame 16 is in the upright position. Whenthe pin 110 is received in the central aperture 100 of the rack 98, theframe 16 is locked in the upright position and cannot pivot relative tothe shock tower 88. When the frame 16 is pivoted from the uprightposition relative to the shock tower 88 and the electric motor 106slides the pin 110 rearwardly such that the pin 110 abuts one of theratchet surfaces 102, the interaction between the pin 110 and theratchet surface 102 it abuts prevents the frame 16 from pivoting furtheraway from the upright position, but permits the frame 16 to pivot backto the upright position such that the pin 110 can be received in thecentral aperture 100, thereby locking the frame 16 in the uprightposition. For example, when the frame 16 is pivoted to the left relativeto the shock tower 88 as shown in FIGS. 9 and 10 and the electric motor106 slides the pin 110 rearward to abut the left ratchet surface 102,the frame 16 is prevented from pivoting further towards the leftrelative to the shock tower 88, but can be pivoted toward the rightrelative to the shock tower 88 up to the upright position. When theelectric motor 106 slides the pin 110 forwardly such that the pin 110 isnot received in the central aperture 100 and does not abut a ratchetsurface 102 of the rack 98, the frame 16 is free to lean relative to theshock tower 88 until one of the stoppers 94 makes contact with itscorresponding contact surface 96 as will be discussed in greater detailbelow. It is contemplated that the electric motor 106 could be replacedby another type of actuator, such as, but not limited to, a hydraulicactuator or a solenoid. It is also contemplated that the rack 98 couldbe connected to the rear side of the shock tower 88, with the ratchetsurfaces 102 facing rearwardly and the locking mechanism 104 mounted toa rear surface of the plate 70.

It is contemplated that the electric motor 106, and therefore theposition of the pin 110, can be controlled by a switch, buttons or anyother input means to be actuated by the driver of the snowmobile 10. Asa result, the driver of the snowmobile 10 can decide to operate thesnowmobile 10 as a leaning vehicle by unlocking the frame 16 from theshock tower 88 or to operate the snowmobile 10 as a more typicalsteer-in-direction snowmobile by locking the frame 16 relative to theshock tower 88. It is also contemplated that the electric motor 106could be controlled to automatically move the pin rearward when thesnowmobile 10 is operated below a predetermined speed or stopped.

The right front suspension assembly 28 will now be described in moredetail. The left front suspension assembly 28 is a mirror image of theright front suspension assembly 28 and will therefore not be describedin detail herein. Elements of the left front suspension assembly 28corresponding to elements of the right front suspension assembly 28 havebeen labeled with the same reference numerals in the figures.

The right front suspension assembly 28 has upper and lower suspensionarms 150, 152, a shock absorber 154 and a ski leg 156.

The upper suspension arm 150 is made of two arms connected at theirdistal ends to form a generally V-shape. The proximal end of the reararm of the upper suspension arm 150 is pivotally connected about anupper suspension arm pivot axis 158 in a recess formed in the extrudedframe member 68. The proximal end of the front arm of the uppersuspension arm 150 is pivotally connected about the upper suspension armpivot axis 158 to the front of plate 84 above the bracket 86. The uppersuspension arm pivot axis 158 is parallel to the pivot axis 92 and, asbest seen in FIG. 4, is slightly laterally offset from the pivot axis 92when the frame 16 is in the upright position. A ball joint 160 isconnected to the distal ends of the two arms of the upper suspensionarms 150. A fastener connects the ball joint 160 to an upper portion ofthe ski leg 156 such that the upper suspension arm 150 is pivotallyconnected to the ski leg 156. More specifically, the ball joint 160 isconnected to a rear wall of the ski leg 156.

The lower suspension arm 152 is made of two arms and a cross-member 162connected between these two arms. The two arms are connected at theirdistal ends by a connector 163 to form a generally V-shape. The proximalend of the rear arm of the lower suspension arm 152 is pivotallyconnected about a lower suspension arm pivot axis 164 in a recess formedin the extruded frame member 68. The proximal end of the front arm ofthe lower suspension arm 152 is pivotally connected about the lowersuspension arm pivot axis 164 between the front of plate 84 and the tabof the bracket 86. The lower suspension arm pivot axis 164 is parallelto the pivot axis 92 and, as best seen in FIG. 4, is slightly laterallyoffset from the pivot axis 92 when the frame 16 is in the uprightposition. The cross-member 162 and its corresponding stopper 80 arearranged such that the cross-member provides a contact surface for thestopper 80 to abut under certain conditions as will be described ingreater detail below. It is contemplated that the stopper 80 could beattached on the cross-member 162 and that a contact surface could beprovided on the frame 16 at the position where the stopper 80 is shownin the figures. A ball joint 166 (FIG. 17) is connected to the connector163 of the lower suspension arms 152 via a connector 168 (FIG. 4). Afastener connects the ball joint 166 to a portion of the ski leg 156that is vertically below and forward of the ball joint 160 such that thelower suspension arm 152 is pivotally connected to the ski leg 156. Morespecifically, the ball joint 166 is connected to a front wall of the skileg 156. The connectors 163 and 168 each have a plurality of aperturesused to fasten the two together. These apertures allow the longitudinalposition of the connector 168 to be changed, which in turn changes thelongitudinal position of the ball joint 166. Changing the position ofthe ball joint 166 changes the caster angle of the ski leg 156. Thecaster angle is the angle between the vertical and a line 170 (FIG. 3)passing through the center of both ball joints 160, 166. It iscontemplated that the longitudinal position of the lower ball joint 166could be modified in other ways. For example, the aperture in one orboth of the connectors 163, 168 could be replaced with slots. It is alsocontemplated that the longitudinal position of the upper ball joint 160could be adjustable instead of or in addition to the adjustability ofthe lower ball joint 166.

The shock absorber 154 includes a hydraulic damper around which isdisposed a coil spring. The lower end of the shock absorber 154 ispivotally connected to a bracket integrally formed with the connector163 of the lower suspension arm 152. The upper end of the shock absorber154 is pivotally connected to the corresponding distal end of the shocktower 88. As can be seen in FIG. 7 for the left end of the shock tower88, a space is formed between the front and rear walls of the shocktower 88 at its distal end to receive the upper end of the shockabsorber 154. As can be seen in FIG. 4 for example, the lower end of theshock absorber 154 is located laterally outwardly of its upper end.

The right ski 26 and its connection to the right ski leg 156 will now bedescribed in more detail. The left ski 26 and its connection to the leftski leg 156 are a mirror image of the right ski 26 and its connection tothe right ski leg 156 and will therefore not be described in detailherein. Elements of the left ski 26 and its connection to the left skileg 156 corresponding to elements of the right ski 26 and its connectionto the right ski leg 156 have been labeled with the same referencenumerals in the figures.

The ski 26 has an upturned front portion, a keel 172 laterally centeredon the bottom of the ski 26, two ribs 174 extending longitudinally onthe top of the ski 26, and a handle 176 connected to the upturnedportion between the ribs 174. It is contemplated that other types ofsnowmobile skis could be used.

The ski 26 is pivotally connected about a pivot axis 177 (FIG. 3) to afirst ski connector 178 (FIG. 9) by a fastener. As can be seen, thefirst ski connector is received between the ribs 174 and is fastened tothe ski 26 near the longitudinal center of the ski 26. As can be seen inFIG. 9, the first ski connector 178 has two longitudinal slots 180. Asecond ski connector 182 is disposed over the first ski connector 178and is connected to it by fasteners passing through the slots 180. Thesecond ski connector 182 has an L-shaped portion adapted to abut thebottom and outer surfaces of the ski leg 156. The second ski connector182 has a number of apertures 184 that permit connection to the ski leg156 at a number of different positions. The apertures 184 and slots 182allow the ski 26 to be selectively moved relative to the ski leg 156along the longitudinal axis of the ski 26. The apertures 184 permit“macro” adjustment, while the slots 182 permit a more precise “micro”adjustment of the position of the ski 26 relative to the ski leg 156. Itis contemplated that the apertures 184 could be replaced by slots. It isalso contemplated that the slots 180 could be replaced by apertures. Itis also contemplated that the first and second ski connectors 178, 182could be replaced by a single ski connector having slots or apertures.It is also contemplated that other adjustment mechanisms could beprovided. For example, the slots or multiple apertures could be providedon the ski leg 156. It is contemplated that in some embodiment, theposition of the ski 26 relative to the ski leg 156 could be fixed.

By changing the position of the ski 26 relative to the ski leg 156 alongthe longitudinal axis of the ski 26, the trail length L (FIG. 3) of theski 26 is changed. The trail length L is the distance between the pointof intersection of a vertical line 186 passing through the pivot axis177 with the ground (line 188, FIG. 3) and the point of intersection ofthe caster line 170 with the ground 188. Changing the caster angle alsochanges the trail length L. The caster angle controls the degree ofself-centering of the ski 26. The trail length L affects the handlingcharacteristics of the snowmobile 10 (i.e. how stable the steering feelsto the driver). Caster and trail length determine in part the amount offorce necessary to steer the skis 26. As explained above, the snowmobile10 can be driven as a leaning vehicle by allowing the frame 16 to pivotrelative to the shock tower 88 or can be driven as a steer-in-directionvehicle by locking the frame 16 to the shock tower 88. As these are twovery different driving conditions, the desired steering forces are notthe same for both conditions.

To steer the skis 26, each ski leg 156 is connected to a steering rod(not shown) via a ball joint 190 (FIGS. 5 and 6) connected to the backof the ski leg 156. The proximal ends of the steering rods are connectedto a pitman arm 192 (FIGS. 5 and 6) connected to the lower portion of asteering column 194. The steering column 194 is connected to the frame16 by lower and upper brackets 196, 198 inside which it can pivot. Apair of connecting rods 200 having ball joints at both ends is connectedbetween a flange 202 (FIG. 4) at a top of the steering column 194 and aflange 204 (FIGS. 5 and 6) near a bottom of the steering column 30,thereby transmitting steering motion between the steering columns 30 and194. The steering column 30 is connected to the frame 16 by lower andupper brackets 206, 208 inside which it can pivot. As a result of thisarrangement, when the handlebar 32, which is connected to the steeringcolumn 30, is turned in one direction, the skis 26 are turned in thesame direction. It is contemplated that the steering columns 30 and 194could be replaced by a single steering column. It is also contemplatedthat the snowmobile 10 could be provided with a power steering systemwhere an actuator, such as an electric motor or a hydraulic actuator,moves the steering rods to steer the skis 26 in response to movement ofthe handlebar 32.

When the frame 16 is locked to the shock tower 88, the snowmobile 10 issteered by turning the handlebar 32 in the direction in which the driverwants to turn. When the frame 16 is not locked to the shock tower 88,the snowmobile 10 is steered by leaning the frame 16 relative to theshock tower 88 in the direction of the turn. To do this, the driver hasto countersteer by momentarily turning the handlebar 32 in the directionopposite to the turn thereby causing a moment that leans the frame 16into the turn. As explained above, the frame 16 pivots about the pivotaxis 92. As can be seen in FIGS. 9 and 10, as the frame 16 pivots aboutthe pivot axis 92, the shock tower 88 remains substantially vertical.

The stoppers 80 and 94 prevent the frame 16 from being pivoted too muchabout the pivot axis 92. An example of the use of the left stoppers 80and 94 will now be provided for the snowmobile 10 making a left turn asshown in FIGS. 9 and 10. It should be understood that for the snowmobile10 making a right turn, the same thing occurs but with the rightstoppers 80 and 94 and their corresponding contact surfaces on the rightside of the snowmobile 10.

As the frame 16 is increasingly pivoted about the pivot axis 92 towardthe left relative to the shock tower 88 to make a left turn, the frame16 eventually reaches an angle where the left contact surface 96 of thetriangular member 76 makes contact with the left stopper 94 mounted onthe shock tower 88. In an exemplary embodiment, this angle is between 45and 60 degrees. Between the upright (i.e. no leaning) and the anglewhere the stopper 94 makes contact with the contact surface 96, theshock tower 88 remains substantially upright and the shock absorbers 154are not compressed as a result of the leaning of the frame 16. When theleft stopper 94 makes contact with the contact surface 96, the force ofthe impact is absorbed in part by the left shock absorber 154, thusreducing the vibrations resulting from the impact being transferred tothe other components of the snowmobile 10 and to the driver and, ifapplicable, his passenger.

Once the left stopper 94 makes contact with the left contact surface 96,the frame 16 can continue to be pivoted toward the left, but in order todo this, the left shock absorber 154 has to be compressed. This can bedone as a result of the angular momentum resulting from the initialleaning of the frame 16 relative to the shock tower 88 when the leftstopper 94 made contact with the left contact surface 96 and/or by thedriver shifting his weight to cause further pivoting of the frame 16.When the frame 16 is leaned after the left stopper 94 has made contactwith the left contact surface 96, not only is the frame 16 pivoted butthe shock tower 88 and the other components of the snowmobile 10 arealso pivoted with it. As the left shock absorber 154 is compressed toprovide further leaning of the snowmobile 10, the left stopper 80 movestoward the cross-member 162 of the lower left suspension arm 152 untilit makes contact with it, thereby preventing any further leaning of thesnowmobile 10 relative to the vertical. In an exemplary embodiment, theamount by which the left shock absorber 154 is compressed when the leftstopper 80 contacts the left cross-member 162 corresponds to a 10 to 20degrees of further leaning of the snowmobile 10 from the angle where theleft stopper 94 made contact with the left contact surface 96. In anembodiment, when the left stopper 80 contacts the left cross-member 162,the lowest part of the fairings 56 is disposed vertically higher than aline 209 (FIG. 10) passing through the lowest point of each ski 26. Thishelps prevent the fairings 56 coming into contact with the ground (i.e.snow), which could otherwise result in the lowest part of the fairings56 becoming a supporting structure of the snowmobile 10 thereby removingweight off the skis 26.

The stoppers 80 and 94 on the right side of the snowmobile 10 limitleaning toward the right by the same angles as the stoppers 80 and 94 onleft side of the snowmobile 10 limit leaning toward the left.

It is contemplated that the stoppers 80, 94 could be useful in limitingleaning on an assisted leaning system as providing the stoppers 80, 94would reduce strain on the leaning actuator which is often used to limitthe leaning.

Turning now to FIGS. 11 and 12, the drive track 34 will be described inmore detail. To facilitate leaning of the frame 16, the track 34 isprovided with an arcuate lateral profile as can be seen in FIG. 12. Theradius of curvature R1 of the track 34 and the radius of curvature R2 ofan arc 210 (FIG. 8) passing through the lateral edges of the groundcontacting surfaces of a ski 26 are selected to be approximately equalto or equal to each other. If the radius R1 is greater than the radiusR2, the rear of the snowmobile 10 will be pushed up as the frame 16 (andtrack 34) leans, thereby removing some pressure from the skis 26.However, this can be at least partially counteracted by changing thelateral distance between the lower and upper suspension arm pivot axes164, 158.

The drive track 34 has central terrain lugs 40A alternating with pairsof outer terrain lugs 40B along the length of the track 34. As can beseen in FIG. 12, the central terrain lugs 40A have a flat centralportion with rounded corners of radius R1 and the outer terrain lugs 40Bhave a rounded edge of radius R1. Between each central terrain lug 40Aand pair of outer terrain lugs 40B is connected an arcuate boss 212 ofradius R1. Each boss 212 is connected by a pair of fasteners 214 to thebelt 216 forming the body of the track 34. As can be seen in FIG. 12,the fasteners 214 protrude from the boss 212 to form cleats, therebyproviding additional traction. The bosses 212 are made of plastic, butit is contemplated that they could be made of other materials such asrubber, in which case they could be integrally formed with the belt 216.The pattern of lugs 40A, 40B is only one possible pattern of terrainlugs and other patterns are contemplated. It is also contemplated thatthe drive track 34 could have generally straight lugs 40A, B. In such anembodiment, it is contemplated that the rear suspension 38 could tiltabout a longitudinal axis.

Turning now to FIGS. 13 to 23, an alternative embodiment of a leaningsnowmobile, snowmobile 300, will be described. For simplicity, elementsof the snowmobile 300 that are similar to those of the snowmobile 10described above will not be described again in detail and have beenlabeled with the same reference numerals.

The snowmobile 300 has a frame 302. The frame 302 includes a tunnel 18,an engine cradle portion 304 and a front suspension assembly portion306. A ski and steering assembly is provided, in which two skis 308 arepositioned at the front end 12 of the snowmobile 300, and are attachedto the front suspension assembly portion 306 of the frame 302 throughfront suspension assemblies 310 that will be described in greater detailbelow.

Turning now to FIGS. 16 and 18, the suspension assembly portion 306 willbe described in more detail. The suspension assembly portion 306 has aframe member (not shown) fastened to the front of the engine cradle 304.The frame member is laterally centered. It is contemplated that theframe member could be replaced by a plurality of beams, tubes and/orbrackets that are fastened, bonded or welded together. Side plates 312are fastened to the left and right sides of the frame member and to thefront of the engine cradle 304. A beam assembly 314 is fastened to frontthe extruded frame member. A generally triangular sheet metal plate 316is disposed forward of the side plates 312 and is fastened along itsbottom to the beam assembly 314 via a bracket 336. The top of thetriangular metal plate 316 is fastened to a tubular frame assembly 318.The tubular frame assembly 318 has two bent tubes 320, two generallyhorizontal tubes 322, two generally vertical tubes 324 and a number ofreinforcement tubes (not numbered for simplicity and clarity of thefigures) disposed between the previously mentioned tubes. The two benttubes 320 are each made of multiple tube sections that are fastened toeach other. The lower ends of the bent tubes 320 are fastened to achannel 326 that is fastened to the front of the beam assembly 314. Fromtheir lower ends, the bent tubes 320 extend forward and upward next toeach other and then extend rearward away from each other. The rear endsof the bent tubes 320 are fastened to the upper end of the engine cradle304. Each generally horizontal tube 322 is connected at its front end toa corresponding one of the bent tubes 320 near a vertical center thereofand to the engine cradle 304 at its rear end. The top of the triangularmetal plate is connected to the generally horizontal tubes 322. The twogenerally vertical tubes 324 are fastened at their top ends to thegenerally horizontal tubes 322 forward of the triangular plate 316. Fromtheir top ends, the generally vertical tubes 324 extend downward towardeach other and are fastened to the top of the beam assembly 314. Aspring support plate 328 (FIG. 19) is fastened to the beam assembly 314forward of the generally vertical tubes 324. Left and right stopperholders 330 (only the left one being shown) are fastened to the sideplates 312 near a front thereof. Left and right stoppers 332 arefastened to their respective stopper holders 330. It is contemplatedthat the stoppers 332 could be integrally formed with the stopperholders 330 or some other portion of the suspension assembly portion306. It is contemplated that the components of the suspension assemblyportion 306 could be made of materials other than metal. For example, itis contemplated that at least some the components of the suspensionassembly portion 306 could be made of plastic or composite material. Itis also contemplated that at least some of the components of thesuspension assembly portion 306 could be connect to each other in anmanner other than the one described above such as in any one of thefollowing manners: bonding, welding or by being integrally formed witheach other. Other manners of connecting elements to each other are alsocontemplated. It is also contemplated that the plates 312 could bereplaced by one or more beams, tubes and/or brackets that are fastened,bonded or welded together. It is also contemplated that one or more ofthe tubes of the tubular frame assembly 318 could be replaced by one ormore beams, plates and/or brackets that are fastened, bonded or weldedtogether.

A shock tower 334 is disposed between the plate 316 and the generallyvertical tubes 324. The lower end of the shock tower 334 is fixedlymounted onto a shaft (not shown). The ends of this shaft are disposedinside bearings (not shown) that are received in apertures insidebrackets 336 (FIG. 18) mounted on top of the beam assembly 314. As aresult, and as will be described in greater detail below, the shocktower 334 can pivot about a pivot axis 338 relative to the frame 302 ofthe snowmobile 300. The pivot axis 338 is laterally aligned with thelongitudinal centerline of the snowmobile 300 when the frame 302 is inan upright position (i.e. the position of the frame 302 shown in FIGS.13 to 16, 18 and 19). The shock tower 334 is generally triangular inshape, but other shapes are contemplated. For example, the shock tower334 could be generally T-shaped with a horizontal bar of the T being ata top of the shock tower 334. The top left and right corners of theshock tower 334 act as left and right stoppers 340. Alternatively, it iscontemplated that separate stoppers could be fastened to the top cornersof the shock tower 334. When the frame 302 leans by a predeterminedangle relative to the shock tower 334, the corresponding stopper 340(i.e. the left stopper 340 when the frame 302 leans left and the rightstopper 340 when the frame 302 leans right) makes contact with acorresponding portion of the tubular frame assembly 318, as will bedescribed in greater detail below. As can be seen in FIG. 16, when theframe 302 is in the upright position as shown, the stoppers 340 arevertically higher than the stoppers 332.

A rack 342 is fastened to the back of the shock tower 334 as shown inFIG. 18. As such, the rack 342 is fixed relative to the shock tower 334.The rack 342 has a central aperture 343 (FIG. 21) located at a lateralcenter of the rack 342 at a top thereof. The rack 342 also has left andright rearward facing ratchet surfaces 344 on either sides of thecentral aperture 343. The central aperture 343 and the ratchet surfaces344 generally define an arc having the pivot axis 338 as a center ofcurvature.

As best seen in FIG. 18, a locking mechanism 346 is mounted to the backof the plate 316. The locking mechanism 346 includes an electric motor348, a cylinder 350 and a pin (not shown). The pin is slidably receivedin the cylinder 350 and passes through an aperture (not shown) in theplate 316 in alignment with the central aperture 343 of the rack 342when the frame 302 is in the upright position. The electric motor 348selectively slides the pin forward such that the pin can be received inthe central aperture 343 of the rack 342 when the frame 302 is in theupright position. When the pin is received in the central aperture 343of the rack 342, the frame 302 is locked in the upright position andcannot pivot relative to the shock tower 334. When the frame 302 ispivoted from the upright position relative to the shock tower 334 andthe electric motor 348 slides the pin forwardly such that the pin abutsone of the ratchet surfaces 344, the interaction between the pin and theratchet surface 344 it abuts prevents the frame 302 from pivotingfurther away from the upright position, but permits the frame 302 topivot back to the upright position such that the pin can be received inthe central aperture 343 of the rack 342, thereby locking the frame 302in the upright position. When the electric motor 348 slides the pinrearward such that the pin is not received in the central aperture 343of the rack 342 and does not abut a ratchet surface 344 of the rack 342,the frame 302 is free to lean relative to the shock tower 334 until oneof the stoppers 340 makes contact with the tubular frame assembly 318 aswill be discussed in greater detail below. It is contemplated that theelectric motor 348 could be replaced by another type of actuator, suchas, but not limited to, a hydraulic actuator or a solenoid. It is alsocontemplated that the rack 342 could be connected to the front side ofthe shock tower 334, with the ratchet surfaces 344 facing forward andthe locking mechanism 346 mounted forwardly thereof.

It is contemplated that the electric motor 348, and therefore theposition of the pin, can be controlled by a switch, buttons or any otherinput means to be actuated by the driver of the snowmobile 300. As aresult, the driver of the snowmobile 300 can decide to operate thesnowmobile 300 as a leaning vehicle by unlocking the frame 302 from theshock tower 334 or to operate the snowmobile 300 as a more typicalsteer-in-direction snowmobile by locking the frame 302 relative to theshock tower 334. It is also contemplated that the electric motor 348could be controlled to automatically move the pin forward when thesnowmobile 300 is operated below a predetermined speed or stopped.

In an alternative embodiment shown in FIG. 24, a section of a brake disc352 is fixedly mounted to the frame 302 in front the shock tower 334 viathe front bracket 336 so as to pivot about the pivot axis 338 with theframe 302. A caliper and brake pad assembly 354 is mounted to the shocktower 334. The caliper and brake pad assembly 354 can be hydraulicallyactuated, via a brake lever for example, by a driver of the snowmobile300 to apply a braking force to the section of the brake disc 352 tostop the leaning of the frame 302 about the pivot axis or to reduce thespeed at which the frame 302 leans. It is contemplated that the brakepad assembly 354 could alternatively be actuated by an electricalactuator. It is contemplated that the section of the brake disc 352could be mounted to the shock tower 334 and the caliper and brake padassembly 354 could be mounted to the frame 302.

Turning back to the embodiment of FIGS. 13 to 23, the spring supportplate 328 supports two torsion springs 356. The springs 356 are disposearound posts 358 extending rearward of the spring support plate 328. Ascan be seen in FIG. 19, when the frame 302 is in the upright positionthe posts 358, and therefore the springs 356, are disposed lower thanthe pivot axis 338 on either side thereof. Each spring 356 has one endportion 360 that extends upwardly and laterally outwardly. The other endof each spring 356 is held in place so as to limit rotation of thespring 356 about its post 358. In the present embodiment, the other endof each spring 356 is held in place by its corresponding plate 312 ascan be seen in FIG. 16. The rack 342 has two bumpers 362 mounted to afront surface thereof. One bumper 362 is mounted at each end of the rack342. As can be seen in FIG. 19, when the frame 302 is in the uprightposition the bumpers 362 are spaced from the end portions 360 of thesprings 356. As will be described in more detail below, when thesnowmobile 300 turns and the frame 302 leans toward the inside of theturn by a certain amount, the bumper 362 on the outside of the turnabuts the end portion 360 of its corresponding spring 356. As a result,the spring applies a force on the rack 342 that is transferred to theshock tower 334, the front suspension assembly 310 on the inside of theturn, and the ski 308 on the inside of the turn. This force that istransferred to the ski 308 disposed on the inside of the turn pushesdown on the ski 308 disposed on the inside of the turn. The more theframe 302 leans, the greater the force generated by the spring 356becomes. In one embodiment, the bumper 362 disposed on the outside ofthe turn starts abutting the end portion 360 of its corresponding spring356 when the center of gravity CG (FIG. 22) of the snowmobile 300 isdisposed laterally outward of the edge of the track 34 disposed insideof the turn. It is contemplated that the springs 356 could be disposedsuch that the bumpers 362 always abut the end portions 360 of thesprings 356. It is contemplated that the springs 356 could be replacedby springs or elastic cords connected between the plate 328 and the endsof the rack 342. It is also contemplated that the springs 356 could bereplaced by a single torsion spring disposed around the pivot axis 338and having both end portions thereof arranged to engage the bumpers 362.

The left front suspension assembly 310 will now be described in moredetail. The right front suspension assembly 310 is a mirror image of theleft front suspension assembly 310 and will therefore not be describedin detail herein. Elements of the right front suspension assembly 310corresponding to elements of the left front suspension assembly 310 havebeen labeled with the same reference numerals in the figures.

The left front suspension assembly 310 has upper and lower suspensionarms 364, 366, a shock absorber 368 and a ski leg 370.

The upper suspension arm 364 is made of two arms connected at theirdistal ends to form a generally V-shape. The proximal end of the reararm of the upper suspension arm 364 is pivotally connected to bracketson the tubular frame assembly 318 about an upper suspension arm pivotaxis 372. The upper suspension arm pivot axis 372 is parallel to thepivot axis 338 and, as best seen in FIG. 19, is slightly laterallyoffset from the pivot axis 338 when the frame 302 is in the uprightposition. The distal ends of the two arms of the upper suspension arm364 is pivotally connected to the upper end of the ski leg 370 about apivot axis 374 as will be described in greater detail below. The pivotaxis 374 is parallel to the pivot axis 372.

The lower suspension arm 366 is made of a front arm, a rear arm, and adiagonal arm. The proximal end of the diagonal arm is connected to theproximal end of the front arm and the distal end of the diagonal arm isconnected to the distal end of the rear arm. The proximal end of therear arm of the lower suspension arm 366 is pivotally connected about alower suspension arm pivot axis 376 to the rear of the rear bracket 336as best seen in FIG. 16. The proximal ends of the front and diagonalarms of the lower suspension arm 366 are pivotally connected about thelower suspension arm pivot axis 376 to the bracket 326 as best seen inFIG. 16. The lower suspension arm pivot axis 376 is parallel to thepivot axis 338 and, as best seen in FIG. 19, is slightly laterallyoffset from the pivot axis 338 when the frame 302 is in the uprightposition. The rear arm of the lower suspension arm 366 provides acontact surface for the stopper 332 to abut under certain conditions aswill be described in greater detail below. It is contemplated that thestopper 332 could be attached on the rear arm of the lower suspensionarm 366 and that a contact surface could be provided on the frame 302 atthe position where the stopper 332 is shown in the FIG. 16. The distalend of the front arm of the lower suspension arm 366 is pivotallyconnected to a front of the ski leg 370 about a pivot axis 378 as willbe described in greater detail below. The distal ends of the rear anddiagonal arms of the lower suspension arm 366 are pivotally connected toa rear of the ski leg 370 about the pivot axis 378 as will be describedin greater detail below. The pivot axis 378 is parallel to the pivotaxis 376

The shock absorber 368 includes a hydraulic damper around which isdisposed a coil spring. The lower end of the shock absorber 368 ispivotally connected to a bracket 380 (FIG. 16) connected to the distalends of the rear and diagonal arms of the lower suspension arm 366. Theupper end of the shock absorber 366 is pivotally connected to thecorresponding distal end of the shock tower 334. As can be seen in FIG.18, for the left end of the shock tower 334, a space is formed betweenthe front and rear sides of the shock tower 334 at its distal end toreceive the upper end of the shock absorber 334 therein. As can be seenin FIG. 19, the lower end of the shock absorber 334 is located laterallyoutwardly of its upper end.

The left ski leg 370, the left ski 308 and its connection to the leftski leg 370 will now be described in more detail. The right ski leg 370,the right ski 308 and its connection to the right ski leg 370 are amirror image of the left ski leg 370, the left ski 308 and itsconnection to the left ski leg 370 and will therefore not be describedin detail herein. Elements of the right ski leg 370, the right ski 308and its connection to the right ski leg 370 corresponding to elements ofthe left ski leg 370, the left ski 308 and its connection to the leftski leg 370 have been labeled with the same reference numerals in thefigures.

With reference to FIGS. 16 to 19, the left ski leg 370 has an outer legportion 382 and an inner leg portion 384. The inner leg portion 384 isdisposed in part inside the outer leg portion 382 and is pivotabletherein. The outer leg portion 382 pivots about a steering axis 386which also corresponds to the caster line. The outer leg portion 382 hasan aperture 388 on a rear side thereof. A steering linkage 390 connectsto the inner leg portion 384 through the aperture 388. The steeringlinkage 390 is connected to the distal end of a steering rod 392 via aball joint. The proximal end of the steering rod 392 is connected to thepitman arm 192 connected to the lower portion of the steering column194.

A connector 394 is connected to the upper end of the outer leg portion382. The distal end of the upper suspension arm 362 is pivotallyconnected to the connector 394 about the axis 374. The connector 394 hasa plurality of apertures (not shown) that allow the connector 394 to beconnected in a plurality of positions to raise or lower the position ofthe distal end of the upper suspension arm 362 relative to the ski 308.A connector 396 is connected to a bracket 398 on the front of the outerleg portion 382. The distal end of the front arm of the lower suspensionarm 364 is pivotally connected to the connector 396 about the axis 378.The connector 396 has a plurality of apertures that allow the connector396 to be connected in a plurality of positions to raise or lower theposition of the distal end of the front arm of the lower suspension arm364 relative to the ski 308. A connector (not shown) is connected to abracket 400 on the rear of the outer leg portion 382. The distal end ofthe rear and diagonal arms of the lower suspension arm 364 are pivotallyconnected to the connector about the axis 378. The bracket 400 has aplurality of apertures that allow the connector to be connected in aplurality of positions to raise or lower the position of the distal endsof the rear arm of the lower suspension arm 364 relative to the ski 308.The apertures in the bracket 400 also allow lower suspension arms havinga geometry different from that of the lower suspension arm 364 to beconnected to the ski leg 370.

A bracket 402 is connected to the lower end of the inner leg portion 384at a rear thereof. The bracket 402 pivots about the steering axis 386with the inner leg portion 384. The bracket 402 has a plurality ofapertures. A lower leg 404 is connected to the bracket 402 via theapertures defined in the bracket 402. The apertures in the bracket 402allow the longitudinal position of the lower leg 404 to be adjusted. Theski 308 is pivotally connected about a pivot axis 406 (FIG. 16) to thelower leg 404 by a fastener. The ski 308 has three sets of apertures towhich the lower leg 404 can be connected.

By changing the position of the ski 308 relative to the ski leg 370along the longitudinal axis of the ski 308 by changing the apertures ofthe bracket 402 to which the lower leg 404 is connected and/or bychanging the aperture of the ski 308 to which the lower leg 404 isconnected, the trail length L′ (FIG. 17) of the ski 308 is changed. Thetrail length L′ is the distance between the point of intersection of avertical line 408 passing through the pivot axis 406 with the ground andthe point of intersection of the caster line (i.e. steering axis 386)with the ground.

A blade 410 is connected to each side of the ski 308. The blades 410extend below the floatation surface of the ski 308. As best seen in FIG.16, each blade 410 has a plurality of holes and slot to allow itslongitudinal and vertical position relative to the rest of the ski 308to be adjusted. It is contemplated that blades having lengths and/orheights different from those of the blades 410 could be used. It is alsocontemplated that the blades 410 could be integrally formed with the ski308.

As best seen in FIG. 19, when the frame 302 is in the upright positionwith the skis 308 being steered in a straight ahead direction, theexternal surfaces of the blades 410 (i.e. the surfaces of the blades 410facing away from a longitudinal centerline of their respective ski 308)are parallel to the pivot axis 412 of the steering column 194 to whichthe pitman arm 192 is connected. Also, in the same arrangement, thepivot axis 412 is parallel to the steering axes 386 of the inner legportions 384. Also, as can be seen in FIG. 16, the pivot axis 412 isalso perpendicular to the pivot axes 372, 374 of the upper suspensionarms 364 and the pivot axes 376, 378 of the lower suspension arms 366.This geometry results in no change in caster and camber when thesuspension assemblies 310 are compressed. Also, this geometry eliminatesbump steering. Bump steering is steering of the skis that can occur insome snowmobiles as a result of the suspension assemblies moving up ordown and not as a result of the user turning the handlebar 32.

To steer the skis 308, each ski leg 370 is connected to a steering rod392 which is also connected to the pitman arm 192 connected to the lowerportion of the steering column 194 as mentioned above. As can be seen inthe figures, the pitman arm 192 and the steering column 194 are disposedforwardly of the shock tower 334. As in the snowmobile 10 describedabove, a pair of connecting rods 200 having ball joints at both ends isconnected between a flange 202 at a top of the steering column 194 and aflange 204. However, in the snowmobile 300, the flange 204 is connectednear a bottom of a steering column 414 as can be seen in FIGS. 17 and18. The steering column 414 is connected to the frame 302 by a lowerbracket 416 and the upper bracket 208 to which the steering column 30 isconnected. A pair of connecting rods 418 having ball joints at both endsis connected between a flange 420 connected to the steering column 414and a flange 422 connected near a bottom of the steering column 30. As aresult, steering motion can be transferred from the steering column 30to the steering column 194 via the steering column 414. It iscontemplated that the steering columns 30, 414 and 194 could be replacedby one, two or more than three steering columns. It is also contemplatedthat the snowmobile 300 could be provided with a power steering systemwhere an actuator, such as an electric motor or a hydraulic actuator,moves the steering rods to steer the skis 308 in response to movement ofthe handlebar 32.

When the frame 302 is locked to the shock tower 334, the snowmobile 300is steered by turning the handlebar 32 in the direction in which thedriver wants to turn. When the frame 302 is not locked to the shocktower 334, the snowmobile 300 is steered by leaning the frame 302relative to the shock tower 334 in the direction of the turn. To dothis, the driver has to countersteer by momentarily turning thehandlebar 32 in the direction opposite to the turn thereby causing amoment that leans the frame 302 into the turn. As explained above, theframe 302 pivots about the pivot axis 338. As can be seen in FIGS. 20 to22, as the frame 302 pivots about the pivot axis 338, the shock tower334 remains substantially vertical.

The stoppers 332 and 340 prevent the frame 302 from being pivoted toomuch about the pivot axis 338. When the frame 302 leans while thesnowmobile 300 turns, the spring 356 disposed on the outside of the turncauses a force to be applied on the ski 308 disposed on the inside ofthe turn to push down on the ski 308 disposed on the inside of the turn.An example of the use of the left stoppers 332 and 340 and the rightspring 356 will now be provided for the snowmobile 300 making a leftturn as shown in FIGS. 20 to 23. It should be understood that for thesnowmobile 300 making a right turn, the same thing occurs but with theright stoppers 332 and 340 and their corresponding contact surfaces onthe right side of the snowmobile 300 and the left spring 356.

As the frame 302 pivots toward the left about the pivot axis 338, theend portion 360 of the right spring 356 eventually makes contact withthe right bumper 362 mounted to the rack 342 (FIG. 20), and applies aforce on the bumper 362. This force is transferred from the bumper 362,to the rack 342 and from the rack 342 to the shock tower 334. As aresult, the upper left end of the shock tower 334 applies a force havinga downward component on the left shock absorber 368, which in turnapplies a force on the left lower suspension arm 366 that is transferredto the left ski leg 370 and ultimately to the left ski 308. Therefore,as a result of the end portion 360 of the right spring 356 makingcontact with the right bumper 362, a force having a downward componentis being applied on the left ski 308, thereby helping to maintain theleft ski 308 in contact with the ground. The more the frame 302 pivotstoward the left about the pivot axis 338, the greater the force beingapplied by the right spring 356 becomes and, as a result, the greaterthe downward component of the force being applied to the left ski 308becomes.

As the frame 302 is increasingly pivoted about the pivot axis 338 towardthe left relative to the shock tower 334 to make a left turn, the frame302 eventually reaches an angle where the left stopper 340 (i.e. theupper left corner of the shock tower 334) makes contact with thegenerally right horizontal tube 322 of the tubular frame assembly 318.In an exemplary embodiment, this angle is between 45 and 60 degrees.Between the upright (i.e. no leaning) and the angle where the leftstopper 340 makes contact with the right horizontal tube 322, the shocktower 334 remains substantially upright and the shock absorbers 368 arenot compressed as a result of the leaning of the frame 302. When theleft stopper 340 makes contact with the right horizontal tube 322, theforce of the impact is absorbed in part by the left shock absorber 368,thus reducing the vibrations resulting from the impact being transferredto the other components of the snowmobile 300 and to the driver and, ifapplicable, his passenger. As best seen in FIG. 21, at the angle wherethe left stopper 340 makes contact with the right horizontal tube 322,the steering columns 192, 414 and 30 are disposed laterally outward of atriangle formed by the connection points of the shock absorber 368 withthe shock tower 334 and the pivot axis 358.

Once the left stopper 340 makes contact with the right horizontal tube322, the frame 302 can continue to be pivoted toward the left, but inorder to do this, the left shock absorber 368 has to be compressed. Thiscan be done as a result of the angular momentum resulting from theinitial leaning of the frame 302 relative to the shock tower 334 whenthe left stopper 340 made contact with the right horizontal tube 322and/or by the driver shifting his weight to cause further pivoting ofthe frame 302. When the frame 302 is leaned after the left stopper 340has made contact with the right horizontal tube 322, not only is theframe 302 pivoted but the shock tower 334 and the other components ofthe snowmobile 300 are also pivoted with it. As the left shock absorber368 is compressed to provide further leaning of the snowmobile 300, theleft stopper 332 moves toward the rear arm of the lower left suspensionarm 366 until it makes contact with it, thereby preventing any furtherleaning of the snowmobile 300 relative to the vertical. In an exemplaryembodiment, the amount by which the left shock absorber 368 iscompressed when the left stopper 332 contacts the rear arm of the lowerleft suspension arm 366 corresponds to a 10 to 20 degrees of furtherleaning of the snowmobile 300 from the angle where the left stopper 340made contact with the right horizontal tube 322. In an embodiment, whenthe left stopper 340 contacts the rear arm of the lower left suspensionarm 366, the lowest part of the fairings 56 is disposed verticallyhigher than a line 424 (FIG. 22) passing through the lowest point ofeach ski 308. This helps prevent the fairings 56 coming into contactwith the ground (i.e. snow for example), which could otherwise result inthe lowest part of the fairings 56 becoming a supporting structure ofthe snowmobile 300 thereby removing weight off the skis 308.

The stoppers 332 and 340 on the right side of the snowmobile 300 limitleaning toward the right by the same angles as the stoppers 332 and 340on left side of the snowmobile 300 limit leaning toward the left.

It is contemplated that the stoppers 332, 340 could be useful inlimiting leaning on an assisted leaning system as providing the stoppers332, 340 would reduce strain on the leaning actuator which is often usedto limit the leaning.

When the left stopper 340 makes contact with the right horizontal tube322, the snowmobile 300 is in its maximum leaning position. In thismaximum leaning position toward the left, the center of gravity CG (FIG.22) of the snowmobile 300 is disposed laterally to the left of thecontact point 426 (FIG. 22) of the left ski 308 with the ground that isaligned with the pivot axis 406 of the left ski 308. As such, as viewedfrom above of the snowmobile 300, the center of gravity CG is alsodisposed outside of a triangle 428 (FIG. 15) defined by the contactpoint 426 of the left ski 308 with the ground that is aligned with thepivot axis 406 of the left ski 308, the contact point 430 (FIG. 22) ofthe right ski 308 with the ground that is aligned with the pivot axis406 of the right ski 308 and the point of intersection 432 of the loadaxis of the track 34 with the ground. The load axis of the track 34 isthe axis along which a force can be applied that would be statisticallyequivalent to the distribution of loads across the contact area betweenthe track 34 and the ground. FIG. 15 shows the triangle 428 when theframe 302 is in the upright position. In FIG. 22, the center of gravityCG is disposed laterally to the right of the contact point 426 (i.e.toward the right side of the snowmobile 300), however in FIG. 22 thesnowmobile 300 is not in its maximum leaning position. As should beunderstood, further leaning of the snowmobile 300 toward the left willplace the center of gravity CG laterally to the left of the contactpoint 426 and therefore outside of the triangle 428 as viewed from abovethe snowmobile 300.

To ensure that the skis 308 do not come into contact with other portionsof the snowmobile 300 when the snowmobile 300 leans and/or the skis 308are turned to steer/countersteer the snowmobile 300 and/or the skis 308pivot about their pivot axis 406 to follow the configuration of theground, recesses 434 are formed in the sides of the snowmobile 300. Theleft recess 434 is disposed to the left of the left side plate 312,forward of the left side panel 436 of the fairings 56 and rearward ofthe left shock absorber 368. The right recess 434 is disposed to theright of the right side plate 312, forward of the right side panel 436of the fairings 56 and rearward of the right shock absorber 368. As canbe seen in FIG. 23, when the snowmobile 300 is in its maximum leaningposition toward the left, with the left ski 308 steered to its maximumposition to countersteer the snowmobile 300 in order to return thesnowmobile 300 to its upright position and with the left ski 308 pivotedabout its pivot axis 406 such the front end of the left ski 308 is inits lowest position and the rear end of the left ski 308 is in itshighest position, the rear end of the left ski 308 is received in theleft recess 434 and does not come into contact with any part of thesnowmobile 300.

Modifications and improvements to the above-described embodiments of thepresent may become apparent to those skilled in the art. The foregoingdescription is intended to be exemplary rather than limiting. The scopeof the present is therefore intended to be limited solely by the scopeof the appended claims.

What is claimed is:
 1. A leaning vehicle comprising: a frame having afront portion and a rear portion; a straddle seat mounted on the frame;a motor supported by the frame; a shock tower pivotally connected to thefront portion of the frame, the frame being pivotable relative to theshock tower about a pivot axis between an upright position and aplurality of leaning positions; at least one biasing member connected tothe frame, the at least one biasing member being adapted to apply afirst force to the shock tower when the frame pivots relative to theshock tower; a front left suspension assembly and a front rightsuspension assembly operatively connected to the front portion of theframe; a front left ground engaging member operatively connected to thefront left suspension assembly; a front right ground engaging memberoperatively connected to the front right suspension assembly; a steeringassembly operatively connected to the front left ground engaging memberand to the front right ground engaging member to steer the vehicle, thesteering assembly having a steering column supported by the frame and ahandlebar connected to the steering column; a rear suspension assemblyoperatively connected to the rear portion of the frame; a rear groundengaging member operatively connected to the rear suspension assembly;each of the front left suspension assembly and the front rightsuspension assembly comprising: a leg operatively connected to acorresponding one of the front left ground engaging member and the frontright ground engaging member, the leg being rotatable about a steeringaxis; an upper suspension arm having a first end pivotally connected tothe frame and a second end pivotally connected to the leg; a lowersuspension arm having a first end pivotally connected to the frame and asecond end pivotally connected to the leg, the lower suspension armbeing lower than the upper suspension arm; and a shock absorber havingan upper end connected to the shock tower and a lower end connected tothe lower suspension arm; the at least one biasing member being adaptedto apply the first force to the shock tower when the frame has pivotedleft relative to the shock tower, the first force being transferred tothe front left ground engaging member by the shock absorber of the frontleft suspension assembly to apply a second force having a downwardcomponent to the front left ground engaging member; and the at least onebiasing member being adapted to apply the first force to the shock towerwhen the frame has pivoted right relative to the shock tower, the firstforce being transferred to the front right ground engaging member by theshock absorber of the front right suspension assembly to apply a thirdforce having a downward component to the front right ground engagingmember.
 2. The vehicle of claim 1, wherein: the at least one biasingmember is a first biasing member and a second biasing member; the firstbiasing member being adapted to apply the first force to the shock towerwhen the frame has pivoted left relative to the shock tower; and thesecond biasing member being adapted to apply the first force to theshock tower when the frame has pivoted right relative to the shocktower.
 3. The vehicle of claim 1, wherein the at least one biasingmember is at least one spring.
 4. The vehicle of claim 3, furthercomprising at least one bumper connected to the shock tower; wherein theat least one spring is adapted to abut the at least one bumper when theframe pivots relative to the shock tower.
 5. The vehicle of claim 4,wherein the at least one spring is spaced from the at least one bumperwhen the frame is in the upright position.
 6. The vehicle of claim 4,wherein: the at least one bumper includes a left bumper connected to aleft side of the shock tower and a right bumper connected to a rightside of the shock tower; the at least one spring includes a left springand a right spring; the right spring being adapted to apply the firstforce to the right bumper when the frame has pivoted left relative tothe shock tower; and the left spring being adapted to apply the firstforce to the left bumper when the frame has pivoted right relative tothe shock tower.
 7. The vehicle of claim 6, wherein the left and rightsprings are spaced from the left and right bumpers when the frame is inthe upright position.
 8. The vehicle of claim 6, further comprising: aleft post connected to the frame, the left post being disposed to a leftof the pivot axis and below the pivot axis when the frame is in theupright position; and a right post connected to the frame, the rightpost being disposed to a right of the pivot axis and below the pivotaxis when the frame is in the upright position; wherein the left andright springs are torsion springs; and wherein the left spring isdisposed around the left post and the right spring is disposed aroundthe right post.
 9. The vehicle of claim 6, further comprising a rackconnected to the shock tower, the rack being movable with the shocktower relative to the frame; wherein the left bumper is connected to aleft side of the rack and the right bumper is connected to a right sideof the rack.
 10. The vehicle of claim 1, further comprising: a leftstopper connected to one of the frame and the shock tower, the leftstopper being adapted to abut another one of the frame and the shocktower when the frame pivots left relative to the shock tower by a firstangle thereby limiting pivoting of the frame relative to the shock towertoward the left; and a right stopper connected to one of the frame andthe shock tower, the right stopper being adapted to abut another one ofthe frame and the shock tower when the frame pivots right relative tothe shock tower by a second angle thereby limiting pivoting of the framerelative to the shock tower toward the right.
 11. The vehicle of claim10, wherein the left stopper is a first left stopper and the rightstopper is a first right stopper; the vehicle further comprising: asecond left stopper connected to one of the frame and the lowersuspension arm of the front left suspension assembly, the second leftstopper being adapted to abut another one of the frame and the lowersuspension arm of the front left suspension assembly when the frame haspivoted left relative to the shock tower by the first angle and theshock absorber of the left suspension assembly is compressed by a firstamount thereby limiting leaning of the vehicle relative to verticaltoward the left; and a second right stopper connected to one of theframe and the lower suspension arm of the front right suspensionassembly, the second right stopper being adapted to abut another one ofthe frame and the lower suspension arm of the front right suspensionassembly when the frame has pivoted right relative to the shock tower bythe second angle and the shock absorber of the right suspension assemblyis compressed by a second amount thereby limiting leaning of the vehiclerelative to vertical toward the right.
 12. The vehicle of claim 10,wherein when one of the left stopper and the right stopper abuts theother one of the frame and the shock tower, the steering column isdisposed laterally outward of a triangle formed by connection points ofthe shock absorbers with the shock tower and the pivot axis.
 13. Thevehicle of claim 1, further comprising: a rack connected to the shocktower, the rack defining a central aperture; and a pin operativelyconnected to the frame and being selectively movable inside the centralaperture, the pin locking the frame in the upright position when the pinis received inside the central aperture.
 14. The vehicle of claim 13,wherein: the rack has a left ratchet surface and a right ratchetsurface; the pin is further selectively movable to abut the left andright ratchet surfaces when the frame is pivoted left and rightrespectively relative to the shock tower; when the pin abuts the leftratchet surface, the left ratchet surface prevents the frame frompivoting further toward the left and permits the frame from pivotingtoward the right up to the upright position where the pin is received inthe central aperture; when the pin abuts the right ratchet surface, theright ratchet surface prevents the frame from pivoting further towardthe right and permits the frame from pivoting toward the left up to theupright position where the pin is received in the central aperture. 15.The vehicle of claim 1, further comprising: a section of a brake discconnected to one of the frame and the shock tower; and a caliper andbrake pad assembly connected to another one of the frame and the shocktower, the caliper and brake pad assembly being adapted to apply abraking force to the section of the brake disc.
 16. The vehicle of claim1, wherein the vehicle is a snowmobile; and wherein: the rear portion ofthe frame includes a tunnel; the front left ground engaging member is aleft ski; the front right ground engaging member is a right ski; therear ground engaging member is an endless track disposed at least inpart under the tunnel; the leg of the front left suspension assembly isa left ski leg; and the leg of the front right suspension assembly is aright ski leg.
 17. The vehicle of claim 16, wherein the endless drivetrack has a generally arcuate lateral profile.
 18. The vehicle of claim16, wherein when the frame is in a maximum leaning position toward aleft and the handlebar is turned to steer the skis toward the left, arear end of the left ski is received in a left recess defined in a leftside of the snowmobile; and wherein when the frame is in a maximumleaning position toward a right and the handlebar is turned to steer theskis toward the right, a rear end of the right ski is received in aright recess defined in a right side of the snowmobile.
 19. The vehicleof claim 18, further comprising: a left side panel connected to theframe rearward of the shock absorber of the front left suspensionassembly; and a right side panel connected to the frame rearward of theshock absorber of the front right suspension assembly; wherein: the leftrecess is disposed rearward of the shock absorber of the front leftsuspension assembly and forward of the left side panel; and the rightrecess is disposed rearward of the shock absorber of the front rightsuspension assembly and forward of the right side panel.
 20. The vehicleof claim 16, further comprising at least one blade connected to at leastone side of each of the left and right skis; wherein the blades extendbelow the floatation surfaces of the left and right skis.
 21. Thevehicle of claim 20, wherein when the frame is in the upright positionand the skis are steered in a straight ahead direction, the blades areparallel to a pivot axis of the steering column.
 22. The vehicle ofclaim 16, wherein when the frame is in a maximum leaning position towarda left, a center of gravity of the snowmobile is disposed to a left of acontact point between the left ski and a ground; and wherein when theframe is in a maximum leaning position toward a right, the center ofgravity of the snowmobile is disposed to a right of a contact pointbetween the right ski and the ground.
 23. The vehicle of claim 1,further comprising fairings connected to the frame; wherein: when theframe is in a maximum leaning position toward a left, a lowest part ofthe fairings when the frame is in the maximum leaning position towardthe left is disposed vertically higher than a line passing through alowest point of the front left ground engaging member and a lowest pointof the front right ground engaging member when the frame is in themaximum leaning position toward the left; and when the frame is in amaximum leaning position toward a right, a lowest part of the fairingswhen the frame is in the maximum leaning position toward the right isdisposed vertically higher than a line passing through a lowest point ofthe front left ground engaging member and a lowest point of the frontright ground engaging member when the frame is in the maximum leaningposition toward the right.
 24. The vehicle of claim 1, furthercomprising: a pitman arm connected to the steering column, the pitmanarm being pivotable with the steering column about a pivot axis of thesteering column; and steering rods connecting the pitman arm to thelegs; wherein the steering axes of the legs are parallel to the pivotaxis of the steering column when the frame is in the upright position.25. The vehicle of claim 24, wherein for each of the front leftsuspension assembly and the front right suspension assembly, the firstend of the upper suspension arm is pivotally connected to the frameabout an upper suspension arm pivot axis and the first end of the lowersuspension arm is pivotally connected to the frame about a lowersuspension arm pivot axis; and wherein the upper suspension arm pivotaxes and the lower suspension arm pivot axes are perpendicular to thepivot axis of the steering column.
 26. A leaning vehicle comprising: aframe having a front portion and a rear portion; a seat mounted on theframe; a motor supported by the frame; a shock tower pivotally connectedto the front portion of the frame, the frame being pivotable relative tothe shock tower about a pivot axis between an upright position and aplurality of leaning positions; a front left suspension assembly and afront right suspension assembly operatively connected to the frontportion of the frame, each of the front left suspension assembly and thefront right suspension assembly comprising a shock absorber having anupper end connected to the shock tower; a front left ground engagingmember operatively connected to the front left suspension assembly, alower end of the shock absorber of the front left suspension assemblybeing operatively connected to the front left ground engaging member; afront right ground engaging member operatively connected to the frontright suspension assembly, a lower end of the shock absorber of thefront right suspension assembly being operatively connected to the frontright ground engaging member; a steering assembly operatively connectedto the front left ground engaging member and to the front right groundengaging member to steer the vehicle, the steering assembly having asteering column supported by the frame and a handlebar connected to thesteering column; a rear suspension assembly operatively connected to therear portion of the frame; a rear ground engaging member operativelyconnected to the rear suspension assembly; and at least one biasingmember connected to the frame, the at least one biasing member applyinga first force to the shock tower when the frame pivots to one of leftand right relative to the shock tower, the first force being transferredto a corresponding one of the front left ground engaging member and thefront right ground engaging member by the shock absorber of acorresponding one of the front left suspension assembly and the frontright suspensions assembly to apply a second force having a downwardcomponent to the corresponding one of the front left ground engagingmember and the front right ground engaging member.
 27. The vehicle ofclaim 26, wherein each of the front left suspension assembly and thefront right suspension assembly further comprises: a leg operativelyconnected to a corresponding one of the front left ground engagingmember and the front right ground engaging member, the leg beingrotatable about a steering axis; an upper suspension arm having a firstend pivotally connected to the frame and a second end pivotallyconnected to the leg; and a lower suspension arm having a first endpivotally connected to the frame and a second end pivotally connected tothe leg, the lower suspension arm being lower than the upper suspensionarm; and the lower end of the shock absorber is connected to the lowersuspension arm.
 28. The vehicle of claim 27, wherein the vehicle is asnowmobile; and wherein: the rear portion of the frame includes atunnel; the front left ground engaging member is a left ski; the frontright ground engaging member is a right ski; the rear ground engagingmember is an endless track disposed at least in part under the tunnel;the leg of the front left suspension assembly is a left ski leg; and theleg of the front right suspension assembly is a right ski leg.
 29. Thevehicle of claim 28, wherein when the frame is in a maximum leaningposition toward a left and the handlebar is turned to steer the skistoward the left, a rear end of the left ski is received in a left recessdefined in a left side of the snowmobile; and wherein when the frame isin a maximum leaning position toward a right and the handlebar is turnedto steer the skis toward the right, a rear end of the right ski isreceived in a right recess defined in a right side of the snowmobile.30. The vehicle of claim 29, further comprising: a left side panelconnected to the frame rearward of the shock absorber of the front leftsuspension assembly; and a right side panel connected to the framerearward of the shock absorber of the front right suspension assembly;wherein: the left recess is disposed rearward of the shock absorber ofthe front left suspension assembly and forward of the left side panel;and the right recess is disposed rearward of the shock absorber of thefront right suspension assembly and forward of the right side panel. 31.The vehicle of claim 28, further comprising at least one blade connectedto at least one side of each of the left and right skis; wherein theblades extend below floatation surfaces of the left and right skis. 32.The vehicle of claim 31, wherein when the frame is in the uprightposition and the skis are steered in a straight ahead direction, theblades are parallel to a pivot axis of the steering column.
 33. Thevehicle of claim 28, wherein when the frame is in a maximum leaningposition toward a left, a center of gravity of the snowmobile isdisposed to a left of a contact point between the left ski and a ground;and wherein when the frame is in a maximum leaning position toward aright, the center of gravity of the snowmobile is disposed to a right ofa contact point between the right ski and the ground.
 34. The vehicle ofclaim 27, further comprising: a pitman arm_connected to the steeringcolumn, the pitman arm being pivotable with the steering column about apivot axis of the steering column; and steering rods connecting thepitman arm to the legs; wherein the steering axes of the legs areparallel to the pivot axis of the steering column when the frame is inthe upright position.
 35. The vehicle of claim 34, wherein for each ofthe front left suspension assembly and the front right suspensionassembly, the first end of the upper suspension arm is pivotallyconnected to the frame about an upper suspension arm pivot axis and thefirst end of the lower suspension arm is pivotally connected to theframe about a lower suspension arm pivot axis; and wherein the uppersuspension arm pivot axes and the lower suspension arm pivot axes areperpendicular to the pivot axis of the steering column.
 36. The vehicleof claim 26, wherein: the at least one biasing member is a first biasingmember; the first biasing member applies the first force to the shocktower when the frame has pivoted left relative to the shock tower, thefirst force being transferred to the front left ground engaging memberby the shock absorber of the front left suspension assembly to apply thesecond force having the downward component to the front left groundengaging member; the vehicle further comprises a second biasing memberconnected to the frame; and the second biasing member applies the firstforce to the shock tower when the frame has pivoted right relative tothe shock tower, the first force being transferred to the front rightground engaging member by the shock absorber of the front rightsuspension assembly to apply the second force having the downwardcomponent to the front right ground engaging member.
 37. The vehicle ofclaim 26, wherein the at least one biasing member is at least onespring.
 38. The vehicle of claim 26, further comprising fairingsconnected to the frame; wherein: when the frame is in a maximum leaningposition toward a left, a lowest part of the fairings when the frame isin the maximum leaning position toward the left is disposed verticallyhigher than a line passing through a lowest point of the front leftground engaging member and a lowest point of the front right groundengaging member when the frame is in the maximum leaning position towardthe left; and when the frame is in a maximum leaning position toward aright, a lowest part of the fairings when the frame is in the maximumleaning position toward the right is disposed vertically higher than aline passing through a lowest point of the front left ground engagingmember and a lowest point of the front right ground engaging member whenthe frame is in the maximum leaning position toward the right.